1 /* $NetBSD: rarp.c,v 1.13 1996/10/13 02:29:05 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1992 Regents of the University of California. 5 * All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Lawrence Berkeley Laboratory and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 40 */ 41 #include <sys/param.h> 42 #include <sys/socket.h> 43 #include <net/if.h> 44 #include <netinet/in.h> 45 46 #include <netinet/if_ether.h> 47 #include <netinet/in_systm.h> 48 49 #include <string.h> 50 51 #include "stand.h" 52 #include "net.h" 53 #include "netif.h" 54 55 static ssize_t rarpsend __P((struct iodesc *, void *, size_t)); 56 static ssize_t rarprecv __P((struct iodesc *, void *, size_t, time_t)); 57 58 /* 59 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 60 */ 61 int 62 rarp_getipaddress(sock) 63 int sock; 64 { 65 struct iodesc *d; 66 register struct ether_arp *ap; 67 struct { 68 u_char header[ETHER_SIZE]; 69 struct { 70 struct ether_arp arp; 71 u_char pad[18]; /* 60 - sizeof(arp) */ 72 } data; 73 } wbuf; 74 struct { 75 u_char header[ETHER_SIZE]; 76 struct { 77 struct ether_arp arp; 78 u_char pad[24]; /* extra space */ 79 } data; 80 } rbuf; 81 82 #ifdef RARP_DEBUG 83 if (debug) 84 printf("rarp: socket=%d\n", sock); 85 #endif 86 if (!(d = socktodesc(sock))) { 87 printf("rarp: bad socket. %d\n", sock); 88 return (-1); 89 } 90 #ifdef RARP_DEBUG 91 if (debug) 92 printf("rarp: d=%x\n", (u_int)d); 93 #endif 94 95 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 96 ap = &wbuf.data.arp; 97 ap->arp_hrd = htons(ARPHRD_ETHER); 98 ap->arp_pro = htons(ETHERTYPE_IP); 99 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 100 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 101 ap->arp_op = htons(ARPOP_REVREQUEST); 102 bcopy(d->myea, ap->arp_sha, 6); 103 bcopy(d->myea, ap->arp_tha, 6); 104 105 if (sendrecv(d, 106 rarpsend, &wbuf.data, sizeof(wbuf.data), 107 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 108 { 109 printf("No response for RARP request\n"); 110 return (-1); 111 } 112 113 ap = &rbuf.data.arp; 114 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 115 #if 0 116 /* XXX - Can NOT assume this is our root server! */ 117 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 118 #endif 119 120 /* Compute our "natural" netmask. */ 121 if (IN_CLASSA(myip.s_addr)) 122 netmask = IN_CLASSA_NET; 123 else if (IN_CLASSB(myip.s_addr)) 124 netmask = IN_CLASSB_NET; 125 else 126 netmask = IN_CLASSC_NET; 127 128 d->myip = myip; 129 return (0); 130 } 131 132 /* 133 * Broadcast a RARP request (i.e. who knows who I am) 134 */ 135 static ssize_t 136 rarpsend(d, pkt, len) 137 register struct iodesc *d; 138 register void *pkt; 139 register size_t len; 140 { 141 142 #ifdef RARP_DEBUG 143 if (debug) 144 printf("rarpsend: called\n"); 145 #endif 146 147 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 148 } 149 150 /* 151 * Returns 0 if this is the packet we're waiting for 152 * else -1 (and errno == 0) 153 */ 154 static ssize_t 155 rarprecv(d, pkt, len, tleft) 156 register struct iodesc *d; 157 register void *pkt; 158 register size_t len; 159 time_t tleft; 160 { 161 register ssize_t n; 162 register struct ether_arp *ap; 163 u_int16_t etype; /* host order */ 164 165 #ifdef RARP_DEBUG 166 if (debug) 167 printf("rarprecv: "); 168 #endif 169 170 n = readether(d, pkt, len, tleft, &etype); 171 errno = 0; /* XXX */ 172 if (n == -1 || n < sizeof(struct ether_arp)) { 173 #ifdef RARP_DEBUG 174 if (debug) 175 printf("bad len=%d\n", n); 176 #endif 177 return (-1); 178 } 179 180 if (etype != ETHERTYPE_REVARP) { 181 #ifdef RARP_DEBUG 182 if (debug) 183 printf("bad type=0x%x\n", etype); 184 #endif 185 return (-1); 186 } 187 188 ap = (struct ether_arp *)pkt; 189 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 190 ap->arp_pro != htons(ETHERTYPE_IP) || 191 ap->arp_hln != sizeof(ap->arp_sha) || 192 ap->arp_pln != sizeof(ap->arp_spa) ) 193 { 194 #ifdef RARP_DEBUG 195 if (debug) 196 printf("bad hrd/pro/hln/pln\n"); 197 #endif 198 return (-1); 199 } 200 201 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 202 #ifdef RARP_DEBUG 203 if (debug) 204 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 205 #endif 206 return (-1); 207 } 208 209 /* Is the reply for our Ethernet address? */ 210 if (bcmp(ap->arp_tha, d->myea, 6)) { 211 #ifdef RARP_DEBUG 212 if (debug) 213 printf("unwanted address\n"); 214 #endif 215 return (-1); 216 } 217 218 /* We have our answer. */ 219 #ifdef RARP_DEBUG 220 if (debug) 221 printf("got it\n"); 222 #endif 223 return (n); 224 } 225